在循环C时退出时出错

时间:2016-03-04 22:47:56

标签: c do-while boolean-logic

我写了一个关于字符串输入和在字符串中查找元音的代码。除了程序没有退出do while循环外,一切正常。

do{
    i = 0; j = 1;
    str = NULL;
    input = '\0';
    for(l = 0; l < 5; l++ ) { /* initializing arrays with zeros */
        lowercase_vowel[l] = 0;
        uppercase_vowel[l] = 0;
    }
    str = (char*)malloc(sizeof(char)); /* allocating space for a character in str */
    printf("\nEnter String : ");
    while(input != '\n' ) /* until user press enter */
        {
            input = getc(stdin); /* taking the input */
            str = (char*)realloc(str,j*sizeof(char)); /* re-allocate memory for character read to be stored */
            str[i] = input;  /* store read character */
            i++;
            j++;
        }
    str[i]='\0';   /* appending null character to the string */

    /*Some calculations here */
    printf("\nDo you want to continure? (Y / N)");
    scanf("%c", &option);
 }while( (option != 'N') || (option != 'n') );

问题是,当我提供选项时,循环不会结束,而且它也会跳过部分

 printf("\nEnter String : "); 

并根据选项中的值进行计算。如果有人帮我解决这个问题,我真的很感激

1 个答案:

答案 0 :(得分:1)

条件

(option != 'N') || (option != 'n')

对于option的任何给定值始终为true。您需要将||(或)替换为&&(和)。